Scientists pinpoint mutations responsible for ineffectiveness of 2014-2015 flu vaccine

Viruses like influenza have the ability to mutate over time, and given that the flu vaccines administered during the 2014-2015 season were largely ineffective at preventing the spread of the flu, it appears the virus that recently circulated had taken on mutations not accounted for when last year's vaccine was developed. Now, researchers have identified specific mutations that influenza recently acquired to escape the current vaccine design.